Radiographic system and method for noninvasively assessing the response of tissue to a compound, such as a therapeutic compound, in vivo. In one embodiment, a non-radioactive, radio-opaque imaging agent accumulates in tissue in proportion to the tissue concentration of a predefined cellular target. The imaging agent is administered to a live organism, and after an accumulation interval, radiographic images are acquired. The tissue being examined is transilluminated by X-ray beams with preselected different mean energy spectra, and a separate radiographic image is acquired during transillumination by each beam. An image processing system performs a weighted combination of the acquired images to produce a first image. The image processing procedure isolates the radiographic density contributed solely by differential tissue accumulation of the imaging agent. A compound is administered to the organism, and after a selected interval, a second radiographic image of the tissue is acquired. Radiographic density contributed by accumulated imaging agent in corresponding areas of tissue in the first and second images are compared. Differences in radiographic density between the images reflect changes in the concentration of the cellular target that have occurred after administration of the compound. The system and method may be used to assess therapeutic efficacy of compounds in the drug discovery process, in clinical trials, and in the evaluation of clinical treatment. In other embodiments, pharmacological and toxicological effects of a wide variety of compounds on tissue in vivo may be noninvasively assessed.
一种无创评估组织对化合物(如治疗化合物)反应的放射性系统和方法。在一种实施例中,一种非放射性、放射性不透明成像剂在组织中积累,其积累量与预定义的细胞靶点的组织浓度成比例。该成像剂被注入到活体
生物中,在积累间隔后,获取放射性图像。正在检查的组织通过预选的不同平均能量谱的X射线束进行透光,并在每个束透光期间获取单独的放射性图像。图像处理系统执行获取的图像的加权组合以产生第一张图像。图像处理过程仅隔离由成像剂的差异组织积累贡献的放射性密度。将化合物注入
生物体后,在选择的时间间隔后,获得组织的第二张放射性图像。比较第一张和第二张图像中相应区域的成像剂积累贡献的放射性密度。图像之间的放射性密度差异反映了化合物注入后细胞靶点浓度发生的变化。该系统和方法可用于评估药物发现过程中化合物的治疗效果,在临床试验中以及评估临床治疗中使用。在其他实施例中,可以无创评估广泛的化合物对活体组织的药理和毒理效应。